OT - point to point wiring - why?

[ethrbunny]

Was wandering Ebay this morning (waiting for my kids to wake up). Looking at Marshalls and saw several with 'point to point' wiring being featured as a selling point. Why? Is there some advantage to this over using a PCB? Isn't copper the same either way? I guess if all the wires are shielded it might make a diff.. but ughh... what a pain to work on.

[MartyMart]

Yeah I guess its a pain to use "point to point" but here's what I think:
Your components are "directly" connected to each other, there can be no
"Bad PCB" solder joint, your "electrical path" is now several tens of cm's
shorter.
Your "PCB" pads wont ever "lift" ... etc etc.
Those re-=issue "Marshall" hand wired amps look FAB and I bet they sound great too .... cheaper than a vintage "Plexi" eh ??

Cheers,
marty.

[casey]

Was wandering Ebay this morning (waiting for my kids to wake up). Looking at Marshalls and saw several with 'point to point' wiring being featured as a selling point. Why? Is there some advantage to this over using a PCB? Isn't copper the same either way? I guess if all the wires are shielded it might make a diff.. but ughh... what a pain to work on.

point to point, if done right is more reliable and hardy on the road.

look into an upper end soldano head, and you'll see what im talking about...

and actually point to point is much easier to work on...

[casey]

look at this:

http://www.aikenamps.com/PCBorPTP.htm

this is a great reference to answer your question directly...


Here is an example:

[petemoore]

Gonna be hard to beat PTP wiring...PCB's...probably pretty close...they say there's mojo in them wires...
 Where I draw the line though [I've heard PCB'd tube amps that IMO work Just Fine..] is tubes in a Printed circuit board...OK....cooling fan to keep the board from getting baked...I definitely prefer nice tube sockets with wires coming off them that goto...where they go to...
 I 'remapped' the entire front end of a PCB, baked from tube heat...PTP wiring the whole thing...THAT fixed it...[lotta messy work, but..]...would have been easier/neater to simply PTP it in the first place....the tubes are still 'in' the PCB, but the PCB is not used for tube pin lug connections...all the connections are now made by wires.
 I've seen these amps that are 30 years or more old, made 'old style' that work just fine...[maybe the caps got replaced etc.] no PCB rot to have to worry about with 'old style' const. techniques...
 It's like the original designers were like "I don't care, I just want it to last...forever"...on alot of the newer stuff...seems like that MojoMotto got lost in translation or something.
 Most of the time tho, [for 'a while' anyway] it probably doesn't make a bit of difference except to the 'purist' amp coniaseur

[casey]

Gonna be hard to beat PTP wiring...PCB's...probably pretty close...they say there's mojo in them wires...
 Where I draw the line though [I've heard PCB'd tube amps that IMO work Just Fine..] is tubes in a Printed circuit board...OK....cooling fan to keep the board from getting baked...I definitely prefer nice tube sockets with wires coming off them that goto...where they go to...
 I 'remapped' the entire front end of a PCB, baked from tube heat...PTP wiring the whole thing...THAT fixed it...[lotta messy work, but..]...would have been easier/neater to simply PTP it in the first place....the tubes are still 'in' the PCB, but the PCB is not used for tube pin lug connections...all the connections are now made by wires.
 I've seen these amps that are 30 years or more old, made 'old style' that work just fine...[maybe the caps got replaced etc.] no PCB rot to have to worry about with 'old style' const. techniques...
 It's like the original designers were like "I don't care, I just want it to last...forever"...on alot of the newer stuff...seems like that MojoMotto got lost in translation or something.
 Most of the time tho, [for 'a while' anyway] it probably doesn't make a bit of difference except to the 'purist' amp coniaseur

bro, i know exactly what you are talking about...if i could count the times i worked on a crate blue voodoo tube amp that was built with the sockets on the board ....   it's just not very wise to construct an amp that way.

what's really irritating is 1/4" sockets directly soldered onto the board....
that type of construction cannot survive the rigors of the road...

[casey]

this is nice:



this is not:

[ninoman123]

Mojo! And its prettier, and like Marty said, easier to debug, plus no bad solder joints. Look at all the pretty components all lined up nice and neat. Oh and plus sometimes when you have a small circuit. I.E a booster or something. Its just easier to solder the leads together instead of whipping up a whole new PCB.

[Dai H.]

Was wandering Ebay this morning (waiting for my kids to wake up). Looking at Marshalls and saw several with 'point to point' wiring being featured as a selling point. Why? Is there some advantage to this over using a PCB? Isn't copper the same either way? I guess if all the wires are shielded it might make a diff.. but ughh... what a pain to work on.

point to point, if done right is more reliable and hardy on the road.

look into an upper end soldano head, and you'll see what im talking about...

and actually point to point is much easier to work on...

SLO100 is PCB...

[Paul Marossy]

Naw, people do PTP because it sounds better!  (and it's an excuse to charge $3000 for an amp) :wink:

There's pros and cons for everything. This is no exception. I'll agree that PTP Is easier to work on.

[Alex C]

SLO100 is PCB...

Yes.  (from Amplifier Chassis Pics www.acplink.com )  


If the SLO100 isn't "upper end," which of theirs is?  I think there's a "Decatone" and other than that, I only know of some smaller combos.  

Here's the inside of a Hot Rod 50 (also from ACP)

[JT]

The whole benefit of PTP is the ease of Modding and fixing. It is a lot easier to work and resolder components. Think of working on a 1971 mustang and then think of working on a 2005 mustang .Ain't happening :!:

[Paul Marossy]

I like the wide foils on those amp PCBs. I feel that the PCBs that Fender is using now have very small tracks for the currents involved, especially where the power tubes are. And, notice how much space is between each track.

[Karmasound]

I read some where that large pcb's added capacitance. True?

I'll try to find it.

[Johnny G]

BADLY designed pcbs MIGHT add in capacitance as a result of tracks being too close together tho in truth crosstalk between signal carrying or B+ tracks in high gain amps is more of a concern

im happy to agree with what mr Aiken says on his site. the difference between a well designed, nicelly made, properllythought out PCB amp with offboard wiring to tubes etc is minimal when compared to to a well made, nicelly organised and properlly planned point to point construction amp.

granted the PTP amp is probablly a bit easier to mod and swap parts but then we're only concerned with that because we like to tinker with stuff

[vanhansen]

bro, i know exactly what you are talking about...if i could count the times i worked on a crate blue voodoo tube amp that was built with the sockets on the board ....   it's just not very wise to construct an amp that way.

what's really irritating is 1/4" sockets directly soldered onto the board....
that type of construction cannot survive the rigors of the road...

I used to own a Blue Voodoo 120.  Called it the Blue Doodoo because that is what it was, and probably still is.  I fried the circuit board in it 3 times.  Had it fixed under warranty all 3 times but after the 3rd time, after I got it back, I sold it and got a Marshall JCM900 2100.  All the tube sockets are PTP.  There are a couple of PCB's in there which I'm fine with.  Unless the PCB is made to withstand the current and heat from the tubes, they're not going to last with tube sockets mounted to them.

[Paul Marossy]

Unless the PCB is made to withstand the current and heat from the tubes, they're not going to last.

That is my feeling. And also why I feel a little nervous about Fender's new PCB designs.  :shock:

[casey]

SLO100 is PCB...

Yes.  (from Amplifier Chassis Pics www.acplink.com )  


If the SLO100 isn't "upper end," which of theirs is?  I think there's a "Decatone" and other than that, I only know of some smaller combos.  

Here's the inside of a Hot Rod 50 (also from ACP)

about 8 years ago i worked on a soldano and it had absolutely no pcb.

i dont know about their more recent stuff....  this was a custom head i worked on with special tolex and the whole bit...

[Satch12879]

I read some where that large pcb's added capacitance.

Large PCB's added capacitance what?

Mesa/Boogies and Bogners are both PCB amps.  Reinhold Bogner has a treatise on PTP vs. PCBs on his website.  Randall Smith of Mesa/Boogie takes great pride in designing his PCBs BY HAND.  Those boards in particular are two sided with plated through holes so that repairs can more easily be performed.  When was the last time you heard of a tech cursing Petaluma for the copper lifing off their boards?

This dribble is a bunch of bollocks if you ask me...

And those amps posted are not truly PTP; real PTP have NO boards (like some real early pedals), just components all hanging to each other, soldered at their leads.  Those in the pictures are called eyelet strip construction or something like that.

[lovekraft0]

This is kinda funny, if you think about it - here's a thread on PTP, and not one picture of a PTP amp in it, not even a terminal strip layout, just tagboards (and that ain't true point to point  :wink: ). FWIW, RG covered this ground pretty much comprehensively quite a while back:

Point to Point Versus PCB Amps - What's the difference?